OBJECTIVE: To verify whether the morphologic evaluation of zygotes and embryos derived from thawed oocytes could provide some relevant information regarding their developmental performance. DESIGN: Fertilization, zygote, and embryo morphology from sibling fresh and frozen oocytes was compared. SETTING: Reproductive Medicine Unit, Società Italiana Studi Medicina della Riproduzione, Bologna, Italy. PATIENT(S): Two hundred thirty-four patients underwent intracytoplasmic sperm injection cycles from which 1,101 spare metaphase II oocytes were cryopreserved. Subsequently, 256 thawing cycles were performed, and 997 oocytes were thawed. INTERVENTION(S): Intracytoplasmic sperm injection was performed on both fresh and frozen oocytes. MAIN OUTCOME MEASURE(S): Fertilization rates, pronuclear zygote morphology, and embryo cleavage rates. RESULT(S): Thawed oocytes had lower chances of being fertilized and developing into top-quality zygotes and regularly cleaving embryos when compared with sibling fresh oocytes irrespective of female age. As a result, the percentage of transferred cycles was significantly lower in frozen cycles compared with fresh cycles (79% and 93%, respectively); the proportion of transferred top-quality embryos followed the same trend. CONCLUSION(S): Reduced fertilization and cleavage rates in frozen cycles when compared with sibling fresh oocytes suggest that, even if surviving thawing, the process of slow freezing has a negative impact on the potential of further growth that is evident as early as the first cleavage divisions. Copyright 2010. Published by Elsevier Inc.
OBJECTIVE: To verify whether the morphologic evaluation of zygotes and embryos derived from thawed oocytes could provide some relevant information regarding their developmental performance. DESIGN: Fertilization, zygote, and embryo morphology from sibling fresh and frozen oocytes was compared. SETTING: Reproductive Medicine Unit, Società Italiana Studi Medicina della Riproduzione, Bologna, Italy. PATIENT(S): Two hundred thirty-four patients underwent intracytoplasmic sperm injection cycles from which 1,101 spare metaphase II oocytes were cryopreserved. Subsequently, 256 thawing cycles were performed, and 997 oocytes were thawed. INTERVENTION(S): Intracytoplasmic sperm injection was performed on both fresh and frozen oocytes. MAIN OUTCOME MEASURE(S): Fertilization rates, pronuclear zygote morphology, and embryo cleavage rates. RESULT(S): Thawed oocytes had lower chances of being fertilized and developing into top-quality zygotes and regularly cleaving embryos when compared with sibling fresh oocytes irrespective of female age. As a result, the percentage of transferred cycles was significantly lower in frozen cycles compared with fresh cycles (79% and 93%, respectively); the proportion of transferred top-quality embryos followed the same trend. CONCLUSION(S): Reduced fertilization and cleavage rates in frozen cycles when compared with sibling fresh oocytes suggest that, even if surviving thawing, the process of slow freezing has a negative impact on the potential of further growth that is evident as early as the first cleavage divisions. Copyright 2010. Published by Elsevier Inc.
Authors: Senthil Kumar Aiyappan; Bulabai Karpagam; V Vadanika; Prem Kumar Chidambaram; S Vinayagam; K C Saravanan Journal: J Clin Diagn Res Date: 2016-01-01
Authors: M Cristina Magli; Markus Montag; Maria Köster; Luigi Muzi; Joep Geraedts; John Collins; Veerle Goossens; Alan H Handyside; Joyce Harper; Sjoerd Repping; Andreas Schmutzler; Katerina Vesela; Luca Gianaroli Journal: Hum Reprod Date: 2011-09-09 Impact factor: 6.918